Piano felt damper.



A. JOHNSON.

PIANO FELT DAMPER.

APPLICATION FILED MAY 7| 1913.'

1,169,832.- l Patented Feb. 1, 1916.

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- ALBERT JoHNsoN, or New YORK, N. Y.

rieNo FirmV DAMPER.

original appliqatioarned september 7, 1912, serial No. 719,138.

- Y 1913. seriaiNo. 766,179.

, To all 'whom t may concern Be -it known that I, ALBERT J orrNsoN, a citizen ofSweden and resident of theborough of Manhattan, inthe countyy of New York and State of New York,have invented certain new and vuseful improvements in Piano Felt Dampers, of which the following f is a specification. v

The above entitled invention is ldivided out from a previous disclosure made by me and forming the subject matter of an alf lowed application for patent, led Sept. 7- 1912, Serial No. 719,188, (Now Patent No. 1,117,577.)

This invention relates particularly i to bass string dampers andaims to provide superior felt-blocks therefor' of the varieties known in the pianomakers art as singlesl doubles and trichord.s.

Blocks of square section cut from a sheet of ordinary piano felt can be torn apart much more easily along planes approximately parallelv to the'original surf-aces of the sheet than along other planes (or by a pull at right angles 'to the original vsurfaces than by yone parallel to the lat-ter); and experience shows that a damper is'more durable if it is so cut and so mounted'that any point on it moves toward theV piano string or wire in aline parallel to the original surface of the felt. This is true of all forms of dampers disclosed herein, each ofl which has a plane ofsymmetry parallelto said surface.- 1 1 Primarily, the invention has for its object to produce' a bass string ydamper of materially stronger construction than those in use heretofore.

'A further object is to provide a novel and advantageous method of making felt-blocks of the type referred to, whereby their wearing qualities will be considerably increased. Other objects and advantages will become apparent as the description proceeds.

Reference will behad tothe accompanying drawing, which is made up of; selected figures from the allowed application afore` said, for a detailed description 4of `this method and the products resulting from its practice, as the invention contemplates.

In the said drawing t--F igure 1 is a com posite view illustrating @.in perspective one end of a sheet of felt from which anumber ofl parallel strips have been cut, some of the.'

latter being completely severed from and .Spcciicaton of Letters Patent.

Patented Feb. 1, 1916.

Divided and this application ined May 7,

`turned up at right angles to the former to show the relative standing position they are to occupy throughout the operation of form lng the damper blocks. Fig. 2 represents in cross-section a device adapted for cutting a V- groove in some of the felt strips, such as Fig. il shows for instance. Fig. 3 is a fragmentary top plan view of the device shown in the preceding ligure, except that -a modified form of cutter is here substituted. Fig. l illustrates part of a finished strip, which when cut cross-wise into short lengths maker. what are known in the trade as single wedge blocks, that is to say, rectangular blocks having each a V-shaped notch attop. Fig. 5 is a transverse section of a device for beveling on either side a strip of the kind represented by Fig. 8. Fig. 6 isa view similar to Fig. 5eXcepting that a` certain side device for cutting the center slit of the strip shown at Fig. 11. Fig. 10 is a broken sectional elevation of the device represented by Fig. 9, Fig. .11 is a fragmentary perspecti ve view of a strip, which when divided up gives trichord wedge blocks the same being similar to those obtained from the strip shown at Fig. 8, but having besides a vertical slit in the top, and Fig. 12is a fragmentary plan view of a piano damper-lever with a felt block attached thereto.

As far as may be practicable, the various elements constituting the several "devices herein described and illustrated will be designated by the same reference characters as wereV employed in the parent application above mentioned.

The initial step in producing1 the divers esY blocks is the cutting up of the felt into strips of'like texture and regular dimensions. This' is effected by taking a sheet of felt suitably fulled and pressed to a uniform thickness, such as indicated at A on the right hand side of Fig. 1, and dividing it up by parallel cuts A1 into rectangular strips a Z2 c having each a width equal to the height of the blocks to be made. The succeeding steps relating to the operations for producing the notch` beveled sides, and slit hereinbeiore retcrred to. constitute what will be termed the shaping7 or trin'imingi for all strips and blocks. The iight yind closely set parallel lines in said Fig. l are not intended to represent peculiar stratihcation of the telt. l ijf indicate what .may be considered,

s well as theoretically, the lines he telt compressed in sheet torni will pa rt the more readily.

To obtain the single wedge blocks, a strip (i is tur.` ed on its edge as represented on the lett hz 4i de ot Fig, l, and thus positioned is piace in the holder shown in Figs. and $3, whicl comprises elongated top and bottom members it() and 2l, hinged together at longitudinal edges, as at 22, and provided with hook catches 53, or other suitable locking means, at their opposite edges. Side retainers or retaining members are located bes tween the atoresaid members 20, 2l and may be carried by the top member. Adjustment ot the side members toward and away from each other to accommodate strips of ditlerent thicknesses (as distinguished from their widths which correspond to the heights o'l' the blocks to beiy is provided ttor by slots 25, receiving the screws 5216. The strip i is held in the box or eli, gated chamber thereby formed, with its grain, that is to say, its severed sui-tace i ermost, as indicated by the vertical lines L, Fig. Q.

il notch in the top or upturned edge oli the si rip n., characteristic oit single wedge blocks, is Yformed by means ot' a cutter orcutter blades QE) guided by longitudinal, downwardly convergent slots 27 in the upper member 20 o'li said holder. Fig. 2 shows a knit'e holder siidable longitiulinallv along the surilace of the .member 2O and carrying two reversely inclined blades 9.9 set in convergent slots and heid b v set-screws 9,0. Through this agency both cuts to fiorm the notch can be made simultaneouslv by moving the tool holder and knives loiigitiuliiially ol" the clamp. Meanwhile the sides ot' the strip (corresponding to its top and bottom respectively when first severed troni the Yteit sheell are confined and tirmljv held between the si de retainers Qi.

in Fig. 3 is shown a single blade 20 held in a holder QS and adapted to cut slantiugly into the upturncd edge ot' the strip /1 so 4as to bevel it inwardly in a .manner analogous to that in which it is operated upon b v the concurrently acting blades 2S). The same result is accomplished with the single blade 29 as with the duplicated knives 2f), though necessarily in successive oiierations.

rFhe outer bevels on the opposite sides ot' the strip L, which represents a double wedge bloei are conveniently liormed in the apparans shown by Figs. 5. 6 and T. which .in general is siniilar to that just described with reference to strip (i. ln this apparatus the top member 20 has a single inclined slot 27, properly disposed to guide the blade 29", so as to bevel the two sides ot' the strip Z), one after the other, the strip Z) being positioned edgewise with relation to the blade and confined precisely as the strip a, in the way previously explained. The blade 29" of coursev held in the tool holder 2S at an angle corresponding to the bevel to be produced. Ats ter one side of the strip is beveled, it turned around end -for end and the other side is reversely beveled. Accordingly one el the side members 2l is reversible as weil as adjustable and is provided with one vertical t'ace and one inclined face. Figs. 5 and 6 show its two positions. The bottom member 21a is provided with a guide groove 27h in its upper side to receive the end of the knife, which projects below the downsturned edge of the strip.

rlhe strip c which is slitted vertically in the center ot' its up-turned edge, and represents a triehord wedge block formed preferably by using the apparatus shown in Figs. 9 and l0. This apparatus is similar to the one employed for shaping strip b, except that its side members 241 both have inversely inclined inner sides, and its tog member 20T has a, vertical slot 2T, with which coperates a vertical knife 290 carried by a holder 28C so as to make the vertical slit in the top oit the strip c. It will be understood that this strip could likewise e shaped in the apparatus ot Flgs. 5-7, previously to insertion in the apparatus last described, 'tor slitting. In either form of apparatus, strip c will be kept standing on edge and subjected to suitable lateral pressure during the shaping or trimming operation, as in the case of either one of the strips a or Let is be observed that, in all of the strips ca c destined to produce 'felt blocks for piano-wire dampers, the severed surface ot' each strip, as parted from the original t'elt sheet, is parallel to the base ot the block, and is intended to be carried foremost at sub stantially right angles to the line ot motion of the block toward the wires of a piano.

The various strips, having been cut ottl the telt sheet, are placed and clamped in holders p (which may be of any suitable construction) with their severed sides presented to the knife. The cutting is eiiected lengthwise of the strip in each instance (not across it) to trim or shape it. As many longitudinal cuts are'made as are necessary to impart the desired shape. In end view or cross section the strip now presents the shape ot' the tinished blocks, which latter are produced by cutting the strip transversely into short lengths` as indicated by the lines n.1, b1, cl. These transverse cuts are at right angles to the longitudinal shaping cuts. The blocks thereby obtained are then ready to be applied to cloth covered veneer to form complete dampers, retaining thereon the peculthe 'llil iar disposition of their severed surfaces relativelyto the bases when made into the finished articles. The application of the blocks to the veneer may be eeoted through the medium of any suitable' adhesive mixture, and constitutes the final step in the production of felt block dampers.

The felt block illustrated in Fig. 12 is of the same general character as the one represented in Fig. 8, the same being mounted on veneer backing 3l which is fastened to a block 32 carried by the piano damper lever, the upper part whereof is shown at 33.

Having described my invention, what I desire to secure by Letters Patent and claim is: y' l l. A damper for pianos, comprising a block severed from sheet felt along planes approximately at rightangles to the original surfaces thereof, and tapered from one of said planes as a base, the block being mounted by said base on the damper lever in position to move therewith on a line substantially perpendicular to the plane of the base.

2. A damper for pianos, comprising a block severed from sheet felt along a plane approximately at a right angle to one of the original surfaces of the felt, said block being trimmed from said plane as a base, and

Copies of this patent `may be obtained for mounted by said base on the damper lever to act upon a piano-string with ,itsv trimmed side inclined to the plane of the base.

3. A damper for pianos, comprising a block severed from sheet felt along a plane approximately at a right angle to an original surface of the felt and its sides trimmed obliquely from said plane as a base, said block being mounted on the damper lever by said base so that the plane of symmetry thereof 'is parallel to ythe line of motion of the block when moved vtoward the piano strings.

4. A damper for pianos, comprising a backing, and a block severed from sheet felt A having one side cut in a plane approximately at right angles'to an original surface of the felt, said side being positioned on said backing and mounted therewith on the damper v lever so that any point on the severed block moves toward the piano strings on a line at right angles to said side.

Signed at the borough of Manhattan in the county of New York and State of New York this 3rd day of May A. D. 1913.

ALBERT JOHNSON.

Witnesses Y H. C. KARLsoN, W. H. GEE.

ve cents each, by addressing the Commissioner of Patents, Washington, .D. C. 

